The present invention relates to steering wheels and in particular to steering wheels which include devices which enable tilting of the steering wheel upon impact of the driver's body in the event of a collision.
It is well known to provide a steering wheel and steering column with an impact energy absorbing deformation member, which absorbs the energy of impact forces by the driver's body in the direction of the axis of the steering column. In conjunction with such deformation members it is also desirable to provide the steering wheel itself with a member which permits the steering wheel to tilt with respect to the axis of the steering column, in order that the angle of the steering wheel plane may conform to the angle of the driver's body, to provide the maximum possible impact area, thereby minimizing the forces on any particular portion of the driver's body.
Prior art deformation members have been known which provide both impact energy absorption for forces along the axis of the steering column and a tilting action of the steering wheel to permit conformance with the angle of the impacting body. One such prior art deformation member is in the form of a pot disposed between the steering wheel hub, which is connected to the steering column, and the steering wheel spokes. Such a pot-shaped member provides deformation and energy absorption along the column axis and also permits tilting of the steering wheel with respect to the column. One problem with such prior art deformation members is that the presence of the pot-shaped element makes it difficult to arrange vehicle controls on the steering column.
Another prior art deformation member which provides for energy absorption of axial forces and enables tilting of the steering wheel is described in published German patent application 2,063,763. That application describes a disk-shaped corrugated sheet, disposed between the steering wheel spokes and the steering wheel hub. Upon impact the disk expands along its axis to absorb impact energy and deforms to permit tilting of the steering wheel. A similar disk-shaped member is described in U.S. Pat. No. 3,586,131. Such deformation members, while requiring less space on the steering column than the pot-shaped members, do require that there be a provision for space into which the member may expand upon deformation.
The present invention is based upon the realization that it is not necessary to provide for absorption of axial force energy and steering wheel tilt by the same deformation member. In accordance with the present invention absorption of axial forces on the steering column is provided by auxiliary energy absorbing members, such as described in German published patent application 1,935,746. Tilting of the steering wheel can therefore be effected by a member which does not also have to absorb axial steering column forces and may therefore be designed to make more efficient use of space on the steering column.
It is therefore an object of the present invention to provide a steering wheel capable of tilting upon impact by a vehicle operator.
It is a further object of the present invention to provide such a steering wheel wherein the deformable member takes up a minimal amount of space on the steering column.